1. Field
The field relates to an organic light emitting diode (OLED) display device and a method of fabricating the same, and more particularly, to an OLED display device and a method of fabricating the same, where the display device has improved mechanical strength because of a plurality of pores formed in a frit to absorb external impact, and has improved adhesion between the upper substrate and the lower substrate because a small height difference between the frit and an upper or lower substrate is filled.
2. Description of the Related Technology
Generally, in an OLED display device, a lower substrate having a pixel region and a non-pixel region is disposed to face an upper substrate for encapsulation, and is coupled to the upper substrate by a sealant such as epoxy.
A plurality of organic light emitting diodes are formed between a scan line and a data line in the pixel region of the lower substrate, and each of the organic light emitting diodes includes an anode electrode, a cathode electrode, and an organic layer having an organic light emitting layer formed between the anode electrode and the cathode electrode.
Since the organic light emitting diode described above includes an organic material, it is vulnerable to hydrogen and oxygen, and since the organic light emitting diode includes the cathode electrode formed of a metallic material as an upper electrode, it is easily oxidized by moisture in the air, and as a result, its electrical and emitting characteristics are degraded. For these reasons, to protect the organic light emitting diode, a powder-type desiccant is disposed on the upper substrate formed of metal, glass or plastic, or a film-type desiccant is attached to the upper substrate, thereby removing moisture permeated from outside.
However, when the powder-type desiccant is used, the process becomes complicated, and the number of materials, production costs and a thickness of the display device are increased. Particularly, the powder-type desiccant is difficult to apply to a top-emission structure. On the other hand, when the film-type desiccant is used, there is a limitation in removing moisture and durability and reliability are reduced, and thus it is difficult to use in mass-production.
To solve these problems, a frit having an excellent encapsulation characteristic due to very low permeability may be formed between the lower substrate and the upper substrate to effectively protect the organic light emitting diode without using a desiccant separately.
However, the frit has poor flexibility and malleability and thus is very vulnerable when it is deformed. Therefore, when the frit is exposed to external impact, a crack may be generated in the frit, so that the organic light emitting diode display device may be damaged or delaminate.